This invention relates to a blasting method which makes use of electronic detonator.
In one respect electronic blasting systems can be divided into systems which are implemented using two wires which interconnect the detonators, and systems which make use of more than two wires.
In a system of the former kind blast times for the various detonators are usually assigned while a blaster is working at a blasting bench.
In a multi-wire system (of the latter kind) the additional wires allow the connection order of the detonators to be established and the wiring order can be used to determine blast timing factors. This type of system can be easier to use as the blaster can readily configure the blast pattern in terms of inter-detonator and inter-row timing increments.
Some blasting systems make use of a location system such as a global positioning system (GPS) to collate the identity of a particular detonator with a geographical location in the blasting system. A blast time is then assigned to the detonator using the geographical coordinates of the detonator in the blast system. A GPS based system, in order to be sufficiently accurate, does however require the use of a GPS reference station. A further factor is that GPS location data may not be sufficiently accurate or readily available, due for example to a rock wall or rock body which blocks reception of a GPS signal.
Although, as noted, a multi-wire blast system is generally easy to use a two-wire blast system has an economic benefit in that the cost of the wire and of the components used to make connections within the system is lower than the cost of a multi-wire system.
The invention is concerned with a blasting system which is readily implemented in a two-wire mode and which, if required, allows the visualisation of a blast pattern.